Some scholars have undertaken studies attempting to establish
super-families, linking for example Indo-European, Uralic and other
families into Nostratic. These attempts have not been
accepted widely because the information necessary to establish
relatedness becomes less available as the time depth is increased.
The time-depth of linguistic methods is limited because of chance
word resemblances and variations between language groups, but a
limit of around 10,000 years is often assumed. The dating of the
various proto-languages is also difficult. Several methods are
available for this but only approximate results can be
obtained.

Evolution into other
fields

Initially, all modern linguistics was historical in
orientation - even the study of modern dialects involved looking at
their origins. But Saussure drew a distinction
between synchronic and diachronic linguistics,
which is fundamental to the present day organization of the
discipline. Primacy is accorded to synchronic linguistics, and
diachronic linguistics is defined as the study of
successive synchronic stages. Saussure's clear demarcation,
however, is now seen to be idealised. In practice, a purely
synchronic linguistics is not possible for any period before the
invention of the gramophone: written records always lag
behind speech in reflecting linguistic developments, and in any
case are difficult to date accurately before the development of the
modern title page.
Also, the work of sociolinguists on linguistic variation
has shown synchronic states are not uniform: the speech habits of
older and younger speakers differ in ways which point to language
change. Synchronic variation is linguistic change in progress.

The biological origin of language is in principle a
concern of historical linguistics, but most linguists regard it as
too remote to be reliably established by standard techniques of
historical linguistics such as the comparative method. Less standard
techniques, such as mass lexical
comparison, are used by some linguists to overcome the
limitations of the comparative method, but most linguists regard
them as unreliable.

The findings of historical linguistics are often used as a basis
for hypotheses about the groupings and movements of peoples,
particularly in the prehistoric period. In practice, however, it is
often unclear how to integrate the linguistic evidence with the
archaeological or genetic evidence. For example, there are a large
number of theories concerning the homeland and early movements of
the Proto-Indo-Europeans, each with
their own interpretation of the archaeological record.

Sub-fields
of study

Comparative linguistics

Comparative linguistics
(originally comparative philology) is a branch of historical
linguistics that is concerned with comparing languages in order to
establish their historical relatedness. Languages may be related by
convergence through borrowing
or by genetic descent, thus languages can evolve and are also able
to cross-relate.

Genetic relatedness
implies a common origin or proto-language, and comparative
linguistics aims to construct language families, to reconstruct
proto-languages and specify the changes that have resulted in the
documented languages. In order to maintain a clear distinction
between attested and reconstructed forms, comparative linguists
prefix an asterisk to any form that is not found in surviving
texts.

Etymology

Etymology is the
study of the history of words—when they entered a language,
from what source, and how their form and meaning have changed over
time. A word may enter a language as a loanword (i.e., as a word from one language
adopted by speakers of another language), through derivational morphology by
combining pre-existing elements in the language, by a hybrid of
these two processes called phono-semantic matching, or in
several other minor ways.

In languages with a long and detailed history, etymology makes
use of philology, the
study of how words change from culture to culture over time.
However, etymologists also apply the methods of comparative linguistics to
reconstruct information about languages that are too old for any
direct information (such as writing) to be known. By analyzing
related languages with a technique known as the comparative
method, linguists can make inferences, about their shared
parent language and its vocabulary. In this way, word
roots have been found which can be traced all the way back to
the origin of, for instance, the Indo-Europeanlanguage
family.

Even though etymological research originally grew from the
philological tradition, nowadays much etymological research is done
in language
families where little or no early documentation is available,
such as Uralic and Austronesian.

Dialectology

Dialectology is
the scientific study of linguistic dialect, the varieties of a language that are
characteristic of particular groups, based primarily on geographic
distribution and their associated features (as opposed to
variations based on social factors, which are studied in sociolinguistics, or variations based
on time, which are studied in historical linguistics. Dialectology
treats such topics as divergence of two local dialects from a
common ancestor and synchronic
variation.

Dialectologists are ultimately concerned with grammatical
features which correspond to regional areas. Thus they are usually
dealing with populations living in their areas for generations
without moving, but also with immigrant groups bringing their
languages to new settlements.

Phonology

Phonology is a
sub-field of historical linguistics which studies the sound system of a specific language or set of languages
change over time. Whereas phonetics is about the physical production
and perception of the
sounds of speech, phonology describes the way sounds function
within a given language or across languages.

An important part of phonology is studying which sounds are
distinctive units within a language. For example, the "p" in "pin"
is aspirated while the same phoneme
in "spin" is not. In some other languages, for example Thai and Quechua, this same difference
of aspiration or non-aspiration does differentiate phonemes.

In addition to the minimal meaningful sounds (the phonemes),
phonology studies how sounds alternate, such as the /p/ in English,
and topics such as syllable structure, stress, accent, and intonation.

The principles of phonological theory have also been applied to
the analysis of sign
languages, even though the phonological units do not consist of
sounds. The principles of phonological analysis can be applied
independently of modality because they are designed
to serve as general analytical tools, not language-specific
ones.

Morphology

Morphology - the study of the
formal means of expression in a language; in the context of
historical linguistics, how the formal means of expression change
over time; for instance, languages with complex inflectional
systems tend to be subject to a simplification process

is the field of linguistics that studies the internal structure
of words as a formal means of expression.[1] Words
as units in the lexicon are the subject matter of lexicology. While words
are generally accepted as being (with clitics) the smallest units of syntax, it is clear that in most (if not all)
languages, words can be related to other words by rules. The rules
understood by the speaker reflect specific patterns (or
regularities) in the way words are formed from smaller units and
how those smaller units interact in speech. In this way, morphology
is the branch of linguistics that studies patterns of
word-formation within and across languages, and attempts to
formulate rules that model the knowledge of the speakers of those
languages, in the context of historical linguistics, how the means
of expression change over time. See grammaticalisation.

Syntax

Syntax is the study of the
principles and rules for constructing sentences in natural
languages. The term syntax is used to refer directly
to the rules and principles that govern the sentence structure of
any individual language, as in "the syntax of Modern Irish". Modern
researchers in syntax attempt to describe
languages in terms of such rules. Many professionals in this
discipline attempt to find general rules
that apply to all natural languages in the context of historical
linguistics, how characteristics of sentence structure in related
languages changed over time. See grammaticalisation.

Comparison
of traditional and modern historical linguistics

There are several differences that occur dealing with the
objects of research of traditional and modern historical
linguistics. The focus of traditional historical linguistics lies
in keeping records of language change in past times of a language
or language family. Modern historical linguistics, however, focuses
on the progress of language change. They try to analyze the cause
or motivation, the spread and the modality of language change.
Traditional historical linguistics concentrates on language and its
changes regarding internal factors. Modern historical linguistics
puts its focal point on external factors e.g. the social
surroundings. That synchrony variates is seen as a key to a
variation in diachrony. The conclusion is that the beginning of a
language change is variation. For traditional historical
linguistics the language structure and the language system are very
important, whereas in modern historical linguistics the language
use and the user are centered. They claim that grammar is shaped by
discourse and language is changed by the speakers. Traditional
historical linguistics is mainly interested in phonology and
morphology and not so much in syntax and semantics. In modern
historical linguistics the main interest lies in syntax, semantics
and pragmatics and no more in phonology. Furthermore traditional
historical linguistics is based on quality while modern historical
linguistics are both qualitative and quantitative. Traditional
historical linguistics deals only with written language but modern
historical linguistics are also concerned with spoken language.

Citations
and notes

^ A
formal language is a set of words, i.e. finite strings of
letters or symbols. The inventory from which these letters are
taken is the alphabet through which the language is
defined. A formal language is often defined by means of a formal grammar,
but it does not describe their semantics (i.e. what they mean)